Multicolor image forming apparatuses such as multicolor printers or multicolor copiers typically include multiple toner containers for containing different color toners. For example, JP-2006-209060-A, JP-2003-084534-A, JP-2007-178969-A, and JP-2008-134524-A (hereinafter respectively “first, second, third, and fourth patent documents”) propose multicolor image forming apparatuses that include multiple image forming units to form different color toner images and a toner container mount in which multiple toner containers containing different color toners are removably installed.
In configurations in which multiple toner containers containing different color toners can be separately installed or removed from the image forming apparatus, when one of the multiple toner containers becomes empty, only the empty toner container can be replaced, thus facilitating replacement of toner containers.
In multicolor image forming apparatuses, generally, consumption of black toner is greater than consumption of any other toners (i.e., yellow, magenta, and cyan toners). Accordingly, it is common that the black toner container is larger in size than toner containers for other colors.
Additionally, in such multicolor image forming apparatuses, if a wrong toner container containing toner of a different color from an intended color is erroneously installed in the toner container mount, different color toners are mixed.
In view of the foregoing, various preventives are tried against erroneous installation of toner containers. For example, in the above-mentioned first patent document, the shape of an engagement portion of the toner container and an engagement portion of the toner container mount that engages the engagement portion of the toner container is different among the different colors to prevent erroneous installation of toner containers.
Additionally, the above-mentioned second, third, and fourth patent documents propose configurations in which toner containers are horizontally inserted and removed from the main body of the image forming apparatus, and each toner container includes a projection projecting from a side surface of the toner container perpendicular to the direction in which the toner container is inserted for preventing erroneous installation. More specifically, the projections for preventing erroneous installation are different in position or shape among different colors. If users try to install the toner container in a wrong portion of the toner container mount, the projection formed on the side of the toner container is blocked by the main body of the apparatus, thus preventing erroneous installation of the toner container. Consequently, the user can recognize that he or she is inserting the toner container into a wrong portion before the toner container reaches the position where the engagement portion of the toner container contacts the engagement portion of the apparatus.